AP Calculus BC : Derivatives

Study concepts, example questions & explanations for AP Calculus BC

varsity tutors app store varsity tutors android store

Example Questions

Example Question #91 : Derivatives

Determine the maximum value attained by the function

.

Possible Answers:

Correct answer:

Explanation:

To find the extrema of , we evaluate the derivative  and find where it is equal to , keeping in mind that we have to actually test the value of  at these (zero-slope) values of  to confirm the function is maximal or minimal there. Therefore we require that

.

By the zero product property, this is true when either  or , so any extrema occur at these values of .

Evaluating the function at these values of  gives 

 

and

,

but since we are seeking the maximum, we conclude that  is the maximum value attained by .

Graph: We see the maximum at  as claimed, and a critical point at , which is neither a local maximum nor minimum.

 Screen shot 2016 03 31 at 5.33.31 pm

Example Question #21 : Finding Maximums

Compute the maximum value attained by the function

.

Possible Answers:

Correct answer:

Explanation:

We use the quotient rule to differentiate  and set the derivative to  to find any extrema.

 

(where in the last step we multiplied both sides by , which is never )

So any extrema occur at

 .

Evaluating the original function at these values of  gives:

.

We choose the larger value and conclude that the maximum value attained by the function is

.

Graph: Both extrema can be seen on the graph of the function below.

 Screen shot 2016 03 31 at 2.24.47 pm

Example Question #1 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

 

Now find the derivative of the function; this will be solved for the value(s) found above.

Since the interval is  satisfies the MVT.

 

Example Question #1 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

 

Then take the difference of the two and divide by the interval.

 

Now find the derivative of the function; this will be solved for the value(s) found above.

Multiple solutions will solve this function, but on the interval , only  fits within, satisfying the MVT.

Example Question #3 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

Now find the derivative of the function; this will be solved for the value(s) found above.

 which falls within the interval , satisfying the MVT.

Example Question #1 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

Now find the derivative of the function; this will be solved for the value(s) found above.

, which falls between , satisfying the MVT.

 

Example Question #2 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

Now find the derivative of the function; this will be solved for the value(s) found above.

 which falls within the interval  satisfying the mean value theorem.

Example Question #4 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

 

Now find the derivative of the function; this will be solved for the value(s) found above.

, which falls within the interval , satisfying the MVT.

Example Question #5 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

Now find the derivative of the function; this will be solved for the value(s) found above.

There are multiple solutions; within the interval  satisfies the mean value theorem.

Example Question #6 : The Mean Value Theorem

Let  on the interval . Find a value for the number(s) that satisfies the mean value theorem for this function and interval.

Possible Answers:

Correct answer:

Explanation:

The mean value theorem states that for a planar arc passing through a starting and endpoint , there exists at a minimum one point, , within the interval  for which a line tangent to the curve at this point is parallel to the secant passing through the starting and end points.

Meanvaluetheorem

In other words, if one were to draw a straight line through these start and end points, one could find a point on the curve where the tangent would have the same slope as this line.

Note that the value of the derivative of a function at a point is the function's slope at that point; i.e. the slope of the tangent at said point.

First, find the two function values of  on the interval 

Then take the difference of the two and divide by the interval.

Now find the derivative of the function; this will be solved for the value(s) found above.

This solution falls within , validating the mean value theorem.

Learning Tools by Varsity Tutors